Hohe Tauern Research Articles

10Be-derived catchment-wide erosion rates from a high-elevation, low-relief landscape in the Gurktal Alps (Austria): comparison with thermochronological data and implications for landscape evolution

In contrast to the mountainous topography and high relief of the Hohe Tauern, the adjacent Nock Mountains (Gurktal Alps) are characterized by hilly topography, lower relief and rounded summits. Although the peculiar landforms in the Nock Mountains have long been recognized, little is known about the rates of landscape evolution in this area. Here we present the first set of 16 10Be-based catchment-wide erosion rates from the Nock Mountains. Our results show that the 10 main catchments erode at rates between ~ 120 and ~ 280 mm/ka. Sub-catchments comprising a high percentage of low-relief surfaces erode at lower rates than the steeper lower parts of the main catchments, which indicates active river incision and relief growth. A comparison between 10Be erosion rates and exhumation rates derived from thermochronology and thermokinematic modelling reveals that short-term and long-term erosion rates are remarkably similar. In the central Nock Mountains, the average 10Be erosion rate (166 ± 35 mm/ka) is almost identical to the average exhumation rate (160 ± 20 m/Ma since ~ 34 Ma). The southern Nock Mountains show a higher 10Be rate (202 ± 58 mm/ka) and a higher long-term exhumation rate (270 ± 30 m/Ma since ~ 18 Ma). The agreement between short-term and long-term erosion rates suggests that average erosion rates in the Nock Mountains did not change significantly during the late Cenozoic. Comparing our data to surrounding regions shows that erosion rates from the Nock Mountains fit to the general W–E decrease in catchment-wide erosion rates observed in the Eastern Alps.Graphical abstract

Rockfall, glacier recession, and permafrost degradation: long-term monitoring of climate change impacts at the Open-Air-Lab Kitzsteinhorn, Hohe Tauern

Abstract. Since 2010, comprehensive geoscientific monitoring has been established in the summit region of the Kitzsteinhorn (“Open-Air-Lab Kitzsteinhorn”), which focuses on the investigation of high-alpine climate change impacts in four monitoring domains: air temperature, glaciation, permafrost, and rock stability. Air and near-surface permafrost temperatures are currently rising with mean rates of almost +0.1 °C yr−1. The thickness of the local cirque glacier is decreasing by more than 1 m yr−1. Rockwall monitoring demonstrates that rockfall activity in freshly deglaciated rockwall sections has increased by 1 order of magnitude. The intensity of the observed processes is most likely unprecedented in recent human history. This emphasizes the importance of long-term monitoring efforts such as those carried out at the Kitzsteinhorn for improved geophysical understanding and for safe and sustainable infrastructure operation in high-alpine environments.

Glaciers and mass movements in the Hüttwinkl Valley (Hohe Tauern range): from the Last Glacial Maximum (LGM) until now

Abstract. The Hüttwinkl Valley, the uppermost section of the Rauris Valley, offers a unique sedimentary and morphological archive to study the development of the landscape in a high-Alpine valley since the Last Glacial Maximum (LGM). Glacial extents of the past, especially during the Younger Dryas (12.8–11.7 ka) and the Little Ice Age, as well as the present-day massive glacier retreat, are clearly recorded. On the other hand, the effects of different mass movements on valley development are evident. The field trip begins in Kolm-Saigurn, where the Durchgangwald landslide occurred in the Bølling–Allerød interstadial (14.7–12.9 ka). In the Younger Dryas (12.9–11.7 ka) glaciers overflowed parts of the Durchgangwald landslide deposit followed by the Lenzanger landslide (Preboreal, Early Holocene). North of Kolm-Saigurn, the Bucheben landslide (Early Holocene) and the Lechnerhäusel landslide (Middle Holocene) showed first a rockslide phase followed by a rock avalanche (sturzstrom), which led to the formation of toma in the distal area. All landslides detached from the western flank of the valley, whereas the eastern slopes are predominantly characterized by slow, deep-seated gravitational slope deformation (DSGSD). The most recent significant mass wasting was caused by rockfalls and catastrophic debris flows.

The summer heatwave in 2022 and its role in changing permafrost and periglacial conditions at a historic mountain pass in the Eastern Alps (Hochtor, Hohe Tauern Range, Austria).

Air temperatures in Europe in 2022 had been the highest on record for the meteorological summer season [June, July and August (JJA)], with +1.3°C above the 1991-2020 average. We studied the effects of recent warming on permafrost and periglacial conditions at a historical mountain pass in the Eastern Alps (Hochtor, 2,576 m asl, 47.08°N, 12.84°E). We used ground temperature data (2010-2022), repeated electrical resistivity tomography measurements (2019, 2022) and auxiliary data dating back to Roman times. We quantified permafrost conditions, evaluated frost-related weathering and slope processes and assessed the impact of atmospheric warming on it. Results show that summer ground surface temperatures increased by 2.5°C between 1891-1920 and 1991-2020, whereas frost-related weathering and periglacial processes decreased. The summers of 2003, 2015, 2019 and 2022 were the four warmest ones in 1887-2022. Hochtor changed in 2010-2022 from an active permafrost site to an inactive one with supra-permafrost talik. A general three-layer structure was quantified for all three ERT profiles measured. The middle, 5-10m thick layer is ice-poor permafrost detected in 2019, whose existence, although smaller, was confirmed in 2022. Resistivity decreased at the three profiles by 3.9% to 5.2% per year, suggesting permafrost degradation. We interpret the resistivity changes between the summers of 2019 and 2022 as a long-term signal of permafrost degradation and not as the single effect of the summer heatwave in 2022. As our data show how rapidly permafrost degrades and as we face an even warmer climate for the remaining part of the 21st century, we expect that near-surface permafrost at the Hochtor site will soon be history.

Mineralogical Composition and Origin of Airborne Dust in an Alpine Environment of Hochtor (Hohe Tauern, Austria): Effects on Pedogenesis, Biological Soil Crusts, and Vascular Plant Growth

There is considerable evidence that mineral dust has an important impact on alpine ecosystems, but the relationship remains unclear in some instances. In an attempt to fill this knowledge gap, we investigated 1) the mineralogical composition of dust components at Hochtor (Hohe Tauern, Austria), 2) its effects on soil formation and biological soil crusts (BSCs), and 3) the effect of mineral dust on plant growth in this interdisciplinary study. Mineral particles such as silicates, carbonates, oxides, volcanic quartz phenocrysts, opaque ore minerals, and spheres, such as microtektites, micrometeorites and fly ash aggregates, were detected using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (SEM-EDX). Rare micrometeorites are of extra-terrestrial origin (cosmic dust) and the decorated spheres are aggregates of fly ashes from anthropogenic origin. In terms of size, fine particles (<100 µm) and coarse particles (>100 µm) characterize the dust composition, originating mainly from adjacent rock outcrops, while the transport from the North African desert appears to be less important and diluted by local sources. The research was carried out as part of the pan-European biodiversity project “Soil Crust International” (SCIN). The results suggest that mineral dust aids in the rapid formation of BSCs in highly disturbed treated plots, and thus, both fine sand and available phosphorus are statistically proven to be determinants of the rapid growth of biocrusts. The number of plant individuals also increases between 2016 and 2020, however at a relatively moderate rate due to permanent mechanical erosion and debris flow within the treatment plots. Silica dust is believed to be a contributing factor to the widespread distribution of silicate plants in limestone habitats, such asPrimula minimaandCerastium uniflorum, two “acidophilic” species that have been tested more closely. Finally, it is deduced that 1) aeolian dust plays a role in the continuous process of soil and crust formation, and 2) it works as a growth regulator in complex biological communities such as BSCs and vascular plant communities by creating new habitats and increasing biodiversity.

Geochemistry of granitoids from the Austroalpine Seckau Complex: a key for revealing the pre-Alpine evolution of the Eastern Alps

Recent studies revealed that the calc-alkaline metagranitoids of the Seckau Complex comprise both (1) a Late Cambrian to Early Ordovician and (2) a Late Devonian to Early Carboniferous (early Variscan) intrusive complex. The older rocks of the Hochreichart Plutonic Suite reflect I to S-type affinity and are peraluminous and characterized by a general decrease in TiO2, Al2O3, MgO, CaO, P2O5, FeOt and MnO with increasing SiO2. Chondrite-normalized rare earth element (REE) plots display a slight enrichment in light rare earth elements (LREE) relative to heavy rare earth elements (HREE) as well as negative Eu anomalies ((Eu/Eu*)N = 0.15- 0.77). The whole-rock initial 87Sr/86Sr ratios calculated back to the time of emplacement (~ 496 Ma) vary between 0.7056 to 0.7061. The early Variscan rocks of the Hintertal Plutonic Suite can be subdivided into (a) the meta- to peraluminous granodioritic suite of the Pletzen Pluton and (b) the peraluminous granitic suite of the Griessstein Pluton. The Pletzen Pluton shows typical magmatic fractionation trends for most of the major oxides and trace elements plotted against SiO2. On a chondrite-normalized diagram, metagranitoids are strongly enriched in LREE and show no significant negative Eu anomaly. Metagranitoids of the Griessstein Pluton have a more peraluminous character and similar major and trace element fractionation trends compared to the Pletzen Pluton. However, the contents in SiO2, major and trace elements clearly point towards a more evolved melt with generally lower TiO2, Al2O3, MgO and CaO values and higher K2O content. Metagranitoids of the Griessstein Pluton are additionally characterized by a slight negative Eu anomaly of about 0.81 on a chondrite-normalized REE plot. Initial 87Sr/86Sr values calculated back to the time of emplacement (~ 353 Ma) of the Pletzen Pluton and the Griessstein Pluton vary between 0.7051—0.7061 and 0.7054—0.7063, respectively, and suggest the same magmatic source for both units. Application of rhyolite-MELTS modelling to the Hintertal Plutonic Suite revealed that the Griessstein Pluton formed by fractional crystallization (~ 30%) from the more primitive Pletzen Pluton. Our geochemical data from the Hochreichart Suite granitoids suggest the existence of a Late Cambrian to Early Ordovician active margin with its remnants now exposed in the Seckau Complex. The early Variscan grainitoids of the Seckau Complex are inferred as part of a magmatic arc along the southern Bohemian active continental margin that was related to the subduction of differently termed oceanic domains (Galicia-Moldanubian Ocean or Paleotethys), prior to the final collision of Gondwana and Laurussia. The general paleogeographic position of the Seckau Complex during the Variscan orogeny is considered to be south to southeast of the Bohemian Massif, adjacent to the eastern Hohe Tauern, the Schladming Tauern, and the Western Carpathians.

Long-term monitoring of high-elevation terrestrial and aquatic ecosystems in the Alps – a five-year synthesis

Whether and how alpine organismic communities respond to ongoing environmental changes is difficult to assess quantitatively, given their intrinsically slow responses, remote locations and limited data. Here we provide a synthesis of the first five years of a multidisciplinary, highly standardized, long-term monitoring programme of terrestrial and aquatic ecosystems in the Austrian Hohe Tauern National Park and companion sites in northern Italy and the central Swiss Alps. The programme aims at evidencing the ecological state and trends in largely late-successional, high-elevation ecosystems. We present the conceptual framework, the study design and first results. Replicated over five regions, different sites and a multitude of permanent plots, the abiotic (microclimate, physics and chemistry of soils and water bodies), biodiversity (plants, animals, microbes), and productivity data (alpine grassland, lakes, streams) provide a representative reference for future re-assessments. The wide spectrum of biological baseline data presented and their spatial and temporal variation also illustrate the degree of uncertainty associated with smaller-scale and short-term studies and the role of stochasticity in long-term biological monitoring.

Littoral macroinvertebrate communities of alpine lakes along an elevational gradient (Hohe Tauern National Park, Austria).

Alpine lakes support unique communities which may respond with great sensitivity to climate change. Thus, an understanding of the drivers of the structure of communities inhabiting alpine lakes is important to predict potential changes in the future. To this end, we sampled benthic macroinvertebrate communities and measured environmental variables (water temperature, dissolved oxygen, conductivity, pH, nitrate, turbidity, blue-green algal phycocyanin, chlorophyll-a) as well as structural parameters (habitat type, lake size, maximum depth) in 28 lakes within Hohe Tauern National Park, Austria, between altitudes of 2,000 and 2,700 m a.s.l. The most abundant macroinvertebrate taxa that we found were Chironomidae and Oligochaeta. Individuals of Coleoptera, Diptera, Hemiptera, Plecoptera, Trichoptera, Tricladida, Trombidiformes, Veneroida were found across the lakes and determined to family level. Oligochaeta were not determined further. Generalized linear modeling and permanova were used to identify the impact of measured parameters on macroinvertebrate communities. We found that where rocky habitats dominated the lake littoral, total macroinvertebrate abundance and family richness were lower while the ratio of Ephemeroptera, Plecoptera and Trichoptera (EPT) was higher. Zoo- and phytoplankton densities were measured in a subset of lakes but were not closely associated with macroinvertebrate abundance or family richness. With increasing elevation, macroinvertebrate abundances in small and medium-sized lakes increased while they decreased in large lakes, with a clear shift in community composition (based on families). Our results show that habitat parameters (lake size, habitat type) have a major influence on benthic macroinvertebrate community structure whereas elevation itself did not show any significant effects on communities. However, even habitat parameters are likely to change under climate change scenarios (e.g. via increased erosion) and this may affect alpine lake macroinvertebrates.

Conventional and UAV-Based Aerial Surveys for Long-Term Monitoring (1954–2020) of a Highly Active Rock Glacier in Austria

Rock glaciers are creep phenomena of mountain permafrost. Speed-up has been observed on several rock glaciers in recent years and attributed to climate change. Although rare, related long-term studies are nevertheless essential to bring a climate perspective to creep velocity changes. In the present study, we focused on changes both in the surface creep velocity and volume of the Leibnitzkopf rock glacier (Hohe Tauern Range, Austria) in the period 1954–2020. We applied 3D change detection using aerial images of both conventional (12 epochs between 1954 and 2018) and unmanned aerial vehicle (UAV)-based aerial surveys (2 epochs, 2019 and 2020), and combined this with ground and air temperature data. Photogrammetric processing (structure-from-motion, multi-view stereo) of the multi-temporal dataset resulted in high-resolution digital orthophotos/DOPs (5–50 cm spatial resolution) and digital elevation models/DEMs (10–50 cm grid spacing). Georeferencing was supported by five externally triangulated images from 2018, bi-temporal aerial triangulation of the image data relying on stable ground around the rock glacier, measured ground control points (2019 and 2020), and measured camera locations (PPK-GNSS) of the UAV flight in 2020. 2D displacement vectors based on the multi-temporal DOPs and/or DEMs were computed. Accuracy analyses were conducted based on geodetic measurements (2010–2020) and airborne laser scanning data (2009). Our analyses show high multi-annual and inter-annual creep velocity variabilities with maxima between 12 (1974–1981) and 576 cm/year (2019–2020), always detected in the same area of the rock glacier where surface disintegration was first observed in 2018. Our volume change analyses of the entire landform for the period 1954–2018 do not indicate any significant changes. This suggests little permafrost ice melt and/or general low ice content of the rock glacier. Analyses of the temperature data reveal a close relationship between higher temperatures and rock glacier acceleration despite the high probability of low ice content. This suggests that hydrogeological changes play an important role in the rock glacier system. The paper concludes with a summary of technical improvements and recommendations useful for rock glacier monitoring and a general view on the kinematic state of the Leibnitzkopf rock glacier.

Increasing Spatio-Temporal Resolution for Monitoring Alpine Solifluction Using Terrestrial Laser Scanners and 3D Vector Fields

This article investigates the usage of terrestrial laser scanner (TLS) point clouds for monitoring the gradual movements of soil masses due to freeze–thaw activity and water saturation, commonly referred to as solifluction. Solifluction is a geomorphic process which is characteristic for hillslopes in (high-)mountain areas, primarily alpine periglacial areas and the arctic. The movement can reach millimetre-to-centimetre per year velocities, remaining well below the typical displacement mangitudes of other frequently monitored natural objects, such as landslides and glaciers. Hence, a better understanding of solifluction processes requires increased spatial and temporal resolution with relatively high measurement accuracy. To that end, we developed a workflow for TLS point cloud processing, providing a 3D vector field that can capture soil mass displacement due to solifluction with high fidelity. This is based on the common image-processing techniques of feature detection and tracking. The developed workflow is tested on a study area placed in Hohe Tauern range of the Austrian Alps with a prominent assemblage of solifluction lobes. The derived displacements were compared with the established geomonitoring approach with total station and signalized markers and point cloud deformation monitoring approaches. The comparison indicated that the achieved results were in the same accuracy range as the established methods, with an advantage of notably higher spatial resolution. This improvement allowed for new insights considering the solifluction processes.

A 6-year lidar survey reveals enhanced rockwall retreat and modified rockfall magnitudes/frequencies in deglaciating cirques

Abstract. Cirque erosion contributes significantly to mountain denudation and is a key element of glaciated mountain topography. Despite long-standing efforts, rates of rockwall retreat and the proportional contributions of low-, mid- and high-magnitude rockfalls have remained poorly constrained. Here, a unique, terrestrial-lidar-derived rockfall inventory (2011–2017) of two glaciated cirques in the Hohe Tauern range, Central Alps, Austria, is analysed. The mean cirque wall retreat rate of 1.9 mm a−1 ranks in the top range of reported values and is mainly driven by enhanced rockfall from the lowermost, freshly deglaciated rockwall sections. Retreat rates are significantly elevated over decades subsequent to glacier downwasting. Elongated cirque morphology and recorded cirque wall retreat rates indicate headward erosion is clearly outpacing lateral erosion, most likely due to the cataclinal backwalls, which are prone to large dip-slope failures. The rockfall magnitude–frequency distribution – the first such distribution derived for deglaciating cirques – follows a distinct negative power law over 4 orders of magnitude. Magnitude–frequency distributions in glacier-proximal and glacier-distal rockwall sections differ significantly due to an increased occurrence of large rockfalls in recently deglaciated areas. In this paper, the second of two companion pieces, we show how recent climate warming shapes glacial landforms, controls spatiotemporal rockfall variation in glacial environments and indicates a transient signal with decadal-scale exhaustion of rockfall activity immediately following deglaciation crucial for future hazard assessments.

Ödenwinkel: an Alpine platform for observational and experimental research on the emergence of multidiversity and ecosystem complexity

Abstract. Studies on ecological successions have a long tradition and have strongly contributed to the understanding of community assembly, niche theory, and ecosystem structure and functionality. Reports on ecological successions are however mostly restricted to one or two taxonomic groups, neglecting the mutual influences and dependencies between multiple taxonomic groups that are the building blocks of diverse communities. We introduce the Alpine research platform Ödenwinkel to promote observational and experimental research on the emergence of multidiversity and ecosystem complexity. We established n= 140 permanent plots along the successional gradient of the forefield of the Ödenwinkelkees glacier at the end of the Stubachtal valley in the Hohe Tauern range (Hohe Tauern National Park, Land Salzburg, Austria). In summer 2019 we completed a first full inventory of biotic and abiotic characteristics of these plots covering the diversity and composition of vascular plants, bryophytes, arthropods, and other animals, bacteria and fungi as well as some geomorphologic properties. In this paper we introduce the design of the research platform and show first results. While focusing on the diversity and composition of vascular plants along the successional gradient, we also provide data on the diversity of animals, bacteria, and fungi. The Ödenwinkel platform will be available as a long-term ecological research site where researchers from various disciplines can contribute to the accumulation of knowledge on ecological successions and on how interactions between various taxonomic groups structure ecological complexity in this Alpine environment.

Spatial ecology of non-breeding Eurasian Griffon Vultures Gyps fulvus in relation to natural and artificial food availability

ABSTRACT Capsule: The movements and spatial ecology of non-breeding Eurasian Griffon Vultures Gyps fulvus in northern Italy, Croatia and Austria do not seem to be affected by feeding station use. Aims: The purpose of this study was to assess how the creation of a feeding station at the Riserva Naturale Regionale del Lago di Cornino (Forgaria nel Friuli, northeast Italy) during the 1980s might have affected the spatial and behavioural ecology of the Eurasian Griffon Vulture. Methods: Using global positioning system (GPS) satellite tracking, we studied movements of nine non-breeding Eurasian Griffon Vultures within the Riserva Naturale Regionale del Lago di Cornino in Italy, the Hohe Tauern in Austria and the Kvarner Gulf in Croatia. Results: Both the average foraging range size and the time spent by the birds in Italy were comparable to those recorded in Croatia and Austria, where the vultures depend on unpredictable food resources. A significant difference in terms of foraging range size was recorded among seasons. In winter it seems to be smaller as a consequence of reduced movements performed by the individuals due to harsh climate conditions. Conclusions: Our results suggest that the creation of a feeding station in Forgaria does not seem to have affected the spatial ecology of the Eurasian Griffon Vulture. However, due to the limited sample size and the young age of the individuals monitored, which have a long dispersal period, the findings presented should be considered as preliminary. Further research needs to be implemented to inform decisions regarding the management of supplementary feeding stations to promote the recovery and conservation of scavenger species, particularly in areas in which they have declined massively.

Experience of Preservation of Traditional Culture and Interaction between Society and State in National Parks of Austria (by Example of National Park “Hohe Tauern”)

On the example of the National Park “Hohe Tauern” some aspects of preservation of traditional culture in national parks of Austria are considered. The raised problem is the subject of interdisciplinary research: history, ethnocultural studies, ethnological regional studies, sociology. The relevance of the study is determined by the risks of loss of identity for a number of ethnic groups, the need to protect, preserve and present their traditional culture. Special attention is paid to the issues of correlation and revival of traditional knowledge, appeal to ethnic self-identification, obtaining economic benefits. The author traces the ways of solving these problems on the basis of the analysis of the experience gained in Austria in the organization of interaction between the population living in the national park, its management, the public and public authorities through the choice of special social technologies, including “folklorism.” Special attention is paid to the orientation of the country’s economy to increase the tourist flow. On the basis of the analysis of the problems the author came to a conclusion that the activities of the National Park “Hohe Tauern” most fully reflects the principles laid down by the Alpine Convention aimed at the development of recreational potential of the territory due to the disclosure of its historical and cultural potential. The experience of the National Park “Hohe Tauern” reflects the effectiveness of international legal documents in the field of sustainable long-term development at the micro level.

КОМБІНОВАНІ ТУРИСТИЧНІ ПОДОРОЖІ ЄВРОПОЮ НА ВЛАСНОМУ АВТОТРАНСПОРТІ ЯК РІЗНОВИД БЕКПЕКІНГУ

The purpose of the study is the analysis of the peculiarities of the organization of budget-limited combined tourist trips through the European countries by private transport as a kind of backpacking. Methods. The paper uses comparison, analysis, synthesis and generalization. The development of tourist routes heavily involved cartographic methods as well as expert assessment of those who took group tours. Results. The study analyses theoretical approaches to the concept of backpacking and its varieties and defines what kind of trips by private transport can be classified as backpacking. Based on the personal experience, we demonstrated organizational, economic and geographic aspects of such trips among domestic tourists as well as directions of further development. We presented examples of organization of two combined trips of tourist groups that involved different kinds of touristic and recreational activities: city excursions, mountaineering, recreation at the sea and lakes. Despite the variety of considered trips, their main purpose was the organization of mountain trekking and climbing peaks. One of the trip's primary destination was the highest peak of Austria, Mount Großglockner and the eponymous high-mountain motorway in the Hohe Tauern National Park. The backpacking trip that took place in July 2019 included trekking through the territory of the Triglav National Park and climbing the highest peak of Slovenia. The main criteria that classify this trip as backpacking are the following: low budget thanks to living in tents and preparing own food; the organization of the trip as a whole as well as trekking routes by the participants themselves without involvement of professional guides. Scientific novelty. The paper studies tours through Europe by private transport as a kind of backpacking tours and the peculiarities of their organization. Practical significance. The suggested variants of tourist trips can be used by self-organized groups as well as professional guides. Another part of European experience that could be useful for Ukraine is the organization of accommodation in the mountains and camping places as well as the system of registration and tourist fees that exist in European countries. The introduction of this practice in Ukraine would encourage better organization of self-organized tourism in the country and filling local budgets and would allow for improvements to the ecological situation in certain popular recreational regions.

Cover Caption

Insect ScienceVolume 25, Issue 6 CONTENTSFree Access Cover Caption First published: 22 November 2018 https://doi.org/10.1111/1744-7917.12526AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Boloria napaea (Hoffmannsegg, 1804) is a species with arctic-alpine disjunction, which has its main area of distribution in the Arctic. In the more southern mountains, it only occurs in the Alps, while a possible occurrence in a restricted region in the eastern Pyrenees remains controversial. Beside special adaptations to the occurring extreme conditions in these ecosystems, the species also represents an example for sexual dimorphism in alpine butterflies. However, the studied population in the Hohe Tauern National Park (Salzburg, Austria) showed no differences in the movement distances between the sexes but three different types of movement. While males showed a high flight activity in a limited part of the area (home range) or rare long dispersal movements, females were less flight active and flew only to find places for oviposition and feeding. This higher flight activity in males may lead to the observed foraging differences between sexes, where male individuals preferred the genera Leontodon and Crepis and females the genera Leontodon and Carduus as nectar sources. We think that sex-specific requirements in nectar ingredients exist; males need more sugar for their intensive flight activity and females have a greater need for amino-acids for their egg production (see pages 1089–1101). Photo by Stefan Ehl. Volume25, Issue6December 2018 RelatedInformation

ROCK GLACIER MONITORING USING AERIAL PHOTOGRAPHS: CONVENTIONAL VS. UAV-BASED MAPPING – A COMPARATIVE STUDY

Abstract. Rock glaciers are creep phenomena of mountain permafrost. Typically, these landforms look like lava flows from a bird’s eye view. Active rock glaciers move downslope with flow velocities in the range of few centimeters to several meters per year. Thus, large masses of rock and ice can be gradually transported down-valley. In this paper we present a comparative study analyzing surface change for Tschadinhorn rock glacier, a relatively fast moving rock glacier located in the Hohe Tauern Range of the Austrian Alps. Aerial photographs (1954–2017) of both metric (conventional) and non-metric (UAV-based) aerial surveys were compared to derive multi-annual to annual flow vector fields and surface height change. For each time interval given we computed a single representative value for flow velocity and, if applicable, also for area-wide surface height change, i.e. volume change. The velocity graph obtained represents the temporal evolution of the kinematics of the rock glacier with good discrimination. Volume change was difficult to quantify since temporal changes were rather small and close to insignificance. The precision and accuracy of the results obtained were numerically quantified. Our study showed that for the Tschadinhorn rock glacier UAV-based aerial surveys can substitute conventional aerial surveys as carried out by national mapping agencies, such as the Austrian Federal Office of Metrology and Surveying (BEV). Thus, UAV-based aerial surveys can help to bridge the data gap between regular aerial surveys. The high accuracy of the UAV-derived results would even allow intra-annual change detection of flow velocity.

Contribution of Saharan Dust to Ion Deposition Loads of High Alpine Snow Packs in Austria (1987–2017)

We investigate the influence of Saharan dust (SD) on the chemical composition and deposition loads of a 31-year long snow chemistry data set (1987 to 2017) of high alpine snow packs situated close to the Sonnblick Observatory, a global GAW (Global Atmospheric Watch) station, in the National Park Hohe Tauern in the Austrian Alps. Based on the snow pack of the winter accumulation period 2015/2016, when two SD events were visible by a reddish color of the snow, we define a pH >5.6 together with a Ca2+ concentration >10µeq/l as thresholds to identify SD affected snow layers (= Saharan Dust Layers, SDLs). This criterion is checked with an intercomparison with trajectories and on-line aerosol data determined at the Sonnblick Observatory. This check was extended to the accumulation periods 2014/15 and 2016/2017 before the whole time series is investigated regarding the contribution of Saharan dust to ion deposition loads. Especially Mg2+, Ca2+ and H+ depositions are strongly affected by SD input causing as average values across the 30 years period increased Mg2+ (25%) and Ca2+ (35%) contributions of SDLs, while the contribution of SDLs to the snow water equivalent (SWE) was only 11%. For H+ SDLs show a much lower contribution (2%) while the contribution of other ions is well comparable to the deposition amount expected according to the SWE of SDLs. The pH range of SDLs covers 5.58 to 7.17, while the median value of all samples is 5.40. The long term trends of ion deposition are not affected by the deposition of Saharan dust.

Polished stone axes from Varna/Nössingbühel and Castelrotto/Grondlboden, South Tyrol (Italy)

A collection of polished stone axes from a late Neolithic site and an Early Bronze Age hill fort in South Tyrol (Italy) have been analysed through a multi-analytical approach, mainly based on non-destructive techniques (i.e. Raman spectroscopy, X-ray fluorescence and prompt gamma activation analysis) to identify the raw materials used in the same area during different periods and compare them with those in use in the surrounding territories. The analytical results suggest raw material exploitation strategies based on local or close sedimentary, metamorphic and magmatic rocks. Most of the artefacts are made from antigoritic serpentinite, whose origin is probably from Hohe Tauern (Austria) or related secondary deposits. These data confirm the importance of such raw material for the production of polished stone axes during recent prehistory and integrate the present knowledge about the distribution of antigoritic artefacts in north-eastern Italy and neighbouring countries.

Unexpected patterns of chironomid larval size in an extreme environment: a highly glaciated, alpine stream

In this article, we report on the development and growth of alpine chironomid species in a highly glaciated headwater, using biometrical analyses. Glacially influenced alpine streams are characterized by year-round harsh environmental conditions. Only a few, highly adapted benthic insects, mainly chironomid larvae (genus Diamesa) live in these extreme conditions. Although several studies have shown patterns in ecosystem structure and function in alpine streams, cause–effect relationships of abiotic components on aquatic insects’ life strategies are still unknown. Sampling was performed at Schlatenbach, a river draining the Schlatenkees (Hohe Tauern NP, Austria), at three sites and on six occasions from August to October 2015. Semi-quantitatively sampled Diamesa cinerella (Meigen 1835) and Diamesa steinboecki (Goetghebuer 1933) larvae were biometrically analysed, and they showed differences in larval size and biovolume with higher values close to the glacier. Considering the decreasing water temperatures but increasing benthic organic matter towards the glacier, food availability seems to play a crucial role for larval size in highly glaciated alpine headwaters. This is the first study to show that harsh conditions in these environments (low temperatures, high turbidity and flow dynamics) may exclude many taxa, but favour other, highly adapted species, when their essential needs (food quality and quantity) are guaranteed.